Steam generator



STEAM GENERATOR Filed Jun 11 1926 2 Sheets-Sheet 1 AMP IN VEN TORS. ./4M& 6 fi/o/y.

ATTORNEY.

R. A. THOM ET AL April 5 STEAM GENERATOR Filed June 11, 1926 2 Sheets-Sheet 2 A TTORNEY.

Patented Apr. 5, 1927.

martian sa nt ES! PATENT O FFlC E,

ROBERT ABSALOM THOM, on BEARDSDEN, NEAR GLASGQW,',AND JAMES- metres ABERDEEN,SCOTLAND,.ASSIGNORS TO. THE SUPERHEATER CtOMrANY, on NEW YORK, N. Y.

This invention relates to improvements in steam genera-tors of the type I having water tube fire-boxes, such for instanceas the steam generator shown and described in -the-speci-- fication of? our 'co-pending application Serial No. 680,510, and has for its principal objectto provide a construction otsteam generator of the'type'indicated in which the usual the Y boxstays at the back plate'or fire-"dooren'd of the fire-box'may be eliminated. Itisa tions, including'that accordingto the'specification of 'saidpriorpatent, water distributors and a water-or steam collector'or receiver are associated with down-flow and upfiow water tubes, constituting the'side Walls of the fire-boxorfurnace'chamber, and wit the'water' and steam spaces of the boiler.

It is'well known that fire-box stays are a source of trouble in steam boiler practice and in the prior constructions having Water tube'side wallsto 'the fire-box, as for instance in our prior patent above referred to,- the usual side and crown stays are eliminatedf As'aboveindicated, by means of the present invention the usual back plate water spacejstays' may also be entirely or almost entirely eliminated.

The present invention principally consists in a-stearn generator of the type having a water tube fire-box, wherein the back plate 'Water'spaceofthe fire-box'is so constructed andassociateclwith other parts of the steam generator and' 'its equipment that the said space constitutes a feed water heater.

A steam generator according to'this in- 'vention comprises appropriately" disposed water distributors'and a water or steam receiver or receivers associated with water heating and steam generatmg' tubes atthe sides of the furnace, the saiddistributors and recelver or receivers being. in 'open'communication at their'forwardends with the body or barrel of the boiler, and having their rear ends secured to the back plate of the boiler and closed by'r'emovable cover plates, means being provided to protect said back plate from the direct action of the furn'ace gases. The means for protectin'g'the said back plate may bea water'space not under boiler pressure and constituting the above mentioned feed water heater, or the back plate maybe protected'by refractory and heat insulating means.

The invention further consists in thesconstruction, combination and arrangement o'f partspointed out-in the appended claims and particularly described" hereinafter? with ref erenceto the accompanying drawings, in which,-

Fig." li's an'elevation; more or less-'dia grammatical, oi the back-plate "0t alocomo tive boiler according to this invention, show ing also a feed pumphereinafterreferred to, and

Fig, 2 isa central longitudinal section through the-fire. box of alocomotive-boiler en' bodyingthis invention, having a back plate a-r-rangementas shown in Fig- 1, the section being taken on theline A-B of F 1 and'look-ing in the direction of the arrow.

Referring to' the drawings, 1, 1: arethe water distributorsand 2 is the steam or steam and Water receiver or collector, 3 and i being the ClOWll-fiOW'l'ilCl up-fiow water tubcsre spectively at theside's of the 'fiie-boX'se'cured at their upper ends to and communicatingwith the distributors 1 and receiver land at their lower'ends to and communicating with headers 5 as in the prior specification above referred to. Preferably the pipes 3 and 4 are formed into pairs, the pipes 'ot 'a pair being united at their ends to, or forged to form, a single portion asshown for connection tothe distributor,- collector or header asth'ecase may be, (Sis the boiler barrel, 7 the smoke tubes, 8 the irontplate of the fire-'boxand 9 the back plate thereoflthe distributors 1 and collector Q-being'in open; communication at their forward-ends with th'e'boiler barrel-as in the'earlier specification reterrechto.

According to this invention the ends o f the- Water distributors 1 and collector 2 at -tl'1e back-plate end of the fire-box are"closed by removable'covers 1 2; accessthus being ob'- tainable for expanding the tubes into the distributors and collect'orand for cleaning, and the distributors andco'llector maybesuit-- ably secured, for instance'directly as-"sh'ow-n, to the back-plate 9, as bybolts' onmpiii'alent means passing through a fiangel'O or 10 preferably inturned, at the end of such distributor or collector and through the backplate 9. Such flangeslO, 10 may conveniently be provided by welding or otherwise securing to the appropriate end portion of each of the distributors and the collector, respectively, an angle ring, the outer pe riphery of which ring is preferably welded to the inner periphery of the distributor or collector.

To protect the back plate from the direct action of the flame and hot furnace gases refractory and heat insulating means may be employed, or a water space 11 notunder the boiler pressure may be employed, and in the latter case the feed water may pass or be passed through the said space 11 from the water tank or tender on its way to the water space of the boiler via the main feed pump or injector (not shown).

In the case of refractory material being employed to protect the back plate, such material may consist of suitably supported fire bricks or slabs and between such bricks or slabs and the back plate one or more sheets of asbestos or other suitable heat insulating material may be placed, such asbestos or other sheeting being preferably strengthened by wire gauze insertions and being secured to the back plate by bolts, preferably galvanized, having their heads sunk in such sheeting. The front plate 8 may be similarly protected by refractory material shown in Fig. 2, 12 being fire bricks or slabs, and 13 asbestos or equivalent sheeting interposed between the fire brick and the plate 8.

As above mentioned the back plate 9 may be protected by a water chamber 11 not under pressure, which may be employed as a feed water heater, and it is this embodiment of the invention which is shown in the drawings. The space 11 between the inner back plate 14 and outer back plate 9, the former constituting the rear plate of the furnace chamber, is provided near its lower end with a connection 15 to the Water tank or feed water supply. The connection 15 leads directly to such tank or supply for use in feeding the back plate water space 11 by gravity or by the natural flow of the water to destroy the vacuum created by the suction of the boiler feed pump or ejector from the said water space, which natural flow will take place as long as the temperature of the water in the said space does not rise to too high a degree. Another connection 16 is provided leading from the discharge outlet of a suitable pump 17 for use in feeding the space 11 from the supply tank should the level of water not be maintained by gravity or natural flow feed. Non-return valves 18, 19 are provided in the connections 15, 16 and the intake of the pump 17 is connected to a pipe 20 leading from the feed water supply. At a suitable height a connection 21 is taken from the back plate water space or feed water heater 11 to the intake of the main feed pump of injector, capable of handling condensing coil in the feed water tank of the engine or tender the outlet from which coil would be above the high water level in said tank and may be down-turned. In order to prevent the pressure in the back plate water space 11 rising above a predetermined degree, say 7 lbs. per square inch, a loaded valve 26 may be provided in a pipe 27 leading back to the water tank of the en gine or tender and this pipe may terminate in the tank in a cooling or condensing coil similarly to the pipe 24.

The pump 17 may be, and preferably is, equipped with an automatic governor adapted to set the pump in action whenever the water in the space 11 falls below a predetermined level. Should the pressure rise above the predetermined degreedue to steam being generated in the feed water heating space 1.1 the valve 26 will open and heated water will flow back to the supply tank through the pipe 27. The water level in the space 11 will. thus fall and the pump 17 will come into operation thus replacing the hot water returned to the tank with cooler water from said tank and thus lowering the temperature in the space 11 and consequently the pressure therein.

In order to enable the back plate water space 11 constituting, according to this embodiment of the invention, a feed water heater to be cleaned when necessary or desirable, asuitable number of wash-out plugs 28 would be provided, such plugs being appropriately located in the back plate, one or more being close to the bottom of the water space and one or more in the upper portion of the back plate. Further, there is preferably provided one or more hand holes in the back plate, closed by suitable covers 29, to enable scrapers to be inserted and manipulated should such be found necessary in oroer to dislodge or remove incrustation from the surfaces of the parts in contact with the water.

The water distributors 1, 1, and the steam and water collector 2, in addition to being secured to the outer back plate 9, are secured to the inner back plate 14 where they pass through such plate and thus tact to stay these lates 9 and 1a, the fire-hole throat ring, i employed, being also secured to both plates and acting as a further staying means. Alternatively the inner and outer back plates may be pressed to shape as shown and secured together at the fire-hole 30.

As above mentioned, the construction according to the present invention is such that the usual fire-box stays in the back water space 11 may be eliminated, owing to the absence of any substantial pressure in said space. It is, however, considered preferable to provide a few stays 31 between the plates 9 and 14, as indicated in Fig. 1.

If desired, in order toprevent the water in the back plate space 11 being heated to an undesirably high degree, the inner back plate 14; may be protected by heat insulating and refractory materials, such for instance as by asbestos sheeting arranged between the said plate 14 and suitable fire bricks or slabs.

Variations may be made in details of construction without departing from the invention.

Having now particularly described and ascertained the nature of our said invention and in what manner the same is to be per formed, we declare that what we claim is:

1. In a boiler, of the locomotive type, a

fire box having a plurality of water cooled Walls, one of said walls forming a water space independent of the Water spaces of the remaining walls, a conduit supplying boiler feed water to said independent water space, and a connection leading from said independent water space to the boiler.

2. In a boiler of the locomotive type, a fire box having a rear wall forming a water space independent of the boiler, a conduit supplying boiler feed water to said rear wall and a. connection leading from the rear wall water space to the boiler.

3. In a boiler of the locomotive type, a fire box having a rear wall forming a. Water space independent of the boiler, means for supplying boiler feed water to said rear wall, a connection leading from the rear wall water space to the boiler, and a pump in said connection whereby said rear wall may be operated at a pressure below that in the boiler.

4. In a boiler of the locomotive type, a fire box having side walls comprising a plurality of steam generating tubes forming a part of the boiler and a rear wall forming a Water space independent of the boiler, aconduit supplying boiler feed water to said rear wall, and a connection leading from the rear vall water space to the boiler.

5. In a boiler of the locomotive type, a plurality of water cooled walls, one of which forms a feed water heater for said boiler, a conduit delivering feed water to said heater by gravity, an'auxlliary pump for torclng feed water thru said heater, and a dischargl conduit leading from the heater to the boiler feed pump.

6. In a boiler of the locomotive type, a tire box having side walls comprising a plurality of steam generating tubes forming part of the boiler, and a rear wall comprising pair of spaced sheets defining a water space separate from the boiler, means for supplying boiler feed water to said rear wall water space, a connection leading from said rear wall water space to the boiler, and a pump in said connection whereby said rear wall may be operated at a pressure below that in the boiler.

7. A locomotive boiler fire box comprising a longitudinal steam and water drum, a pair or" spaced headers located below said drum, steam generating tubes connecting said drum with each of said headers and defining the side walls of said fire box, a pair of spaced sheets closing the space between said drum and headers at one end thereof to form the rear wall of said fire. box, said sheets defining a water space separate from the boiler, means for supplying boiler feed water to said rear wall water space, and a connection leading from said rear, wall water space to the boiler.

ROBERT ABSALOM THOM: JAMES THOM. 

